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{-# LANGUAGE GADTs, TypeFamilies #-}
module T10562 where
type family Flip a
data QueryRep qtyp a where
QAtom :: a -> QueryRep () a
QOp :: QueryRep (Flip qtyp) a -> QueryRep qtyp a
instance Eq (QueryRep qtyp a) where
(==) = error "urk"
instance (Ord a) => Ord (QueryRep qtyp a) where
compare (QOp a) (QOp b) = a `compare` b
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